Patients with hypogammaglobulinemia require replacement therapy with intravenous gammaglobulin. At present, the only source of gammaglobulin for patients use is from donors of human plasma. Recently, the dangers of transmitting viral infections through the use of human blood products have ben re-emphasized after reports of hepatitis C infection in patients treated with contaminated immune globulin. The overall goal of this multicenter study is to test the safety of a gammaglobulin product (RPR 109413) prepared by a new method by the Armour Pharmaceutical Company, a subsidiary of Rhone-Poulenc Rorer. RPR 109413 is a highly purified, liquid intravenous immunoglobulin (IVIG) product. Its primary difference from currently marketed IVIG products is that it includes q wet heat treatment (pasteurization) as an additional safeguard against viruses. The present study is part of a double-blind randomized Phase II comparison of the safety, tolerance, efficacy, and biological half life of RPR 109413 and Gamimmune N (10% solution) administered intravenously at a dose ranging from 200 mg/kg to 600 mg/kg to approximately 81 patients with primary or secondary immune deficiency characterized by defective antibody synthesis. We have enrolled 11 patients at this center.